Electrically assisted power steering system for motor vehicles

Abstract

An electrically assisted power steering system for motor vehicles includes an input shaft ( 2 ) that is in working engagement with a steering wheel ( 4 ). The input shaft ( 2 ) is used to transfer a torque necessary for steering wheels that are to be steered. An output member is in working engagement with the wheels to be steered. An electric motor ( 7 ), by way of which a power assist may be exerted on the input shaft ( 2 ) or the output member, is arranged on the power steering system. A detection unit ( 10 ) is provided to ascertain the parameters for the equipment variant of the vehicle present in each case. The ascertained parameters are conveyed to the electronics unit ( 9 ) for adapted control of the electric motor ( 7 ). The parameters for the equipment variant of the vehicle present in each case include values for the specific front axle load of the vehicle and/or for the tire characteristic of the vehicle.

What is claimed is:  
     
       1. An electrically assisted power steering system for a motor vehicle, comprising: 
       an input shaft in engagement with a steering wheel of the motor vehicle;  
       an output member in engagement with wheels of the motor vehicle to be steered;  
       an electric motor configured to transmit a power assist on one of the input shaft and the output member;  
       a sensing unit configured to sense at least one steering-specific parameter, the at least one steering-specific parameter including a direction and intensity of a steering torque imparted on the input shaft;  
       an electronics unit configured to process the at least one steering-specific parameter and to control the electric motor; and  
       a detection unit configured to determine at least one parameter relating to a steering characteristic of an equipment variant present in the motor vehicle and to transmit the determined at least one parameter to the electronics unit, the electronics unit configured to control the electric motor in accordance with the determined at least one parameter relating to the steering characteristic of the equipment variant present in the motor vehicle;  
       wherein the at least one parameter relating to the steering characteristic of the equipment variant present in the motor vehicle includes a parameter representing at least one tire characteristic of the motor vehicle; and  
       wherein a plurality of tire versions are combined to define at least one characteristic group in accordance with the at least one tire characteristic.  
     
     
       2. The electrically assisted power steering system according to  claim 1 , wherein the at least one parameter relating to the steering characteristic of the predetermined equipment variant present in the motor vehicle includes at least one of a parameter representing a front axle load of the vehicle and parameters representing respective chassis springs associated with different front axle loads. 
     
     
       3. The electrically assisted power steering system according to  claim 1 , wherein the at least one tire characteristic includes at least one of a tire slip stiffness, a force/deformation behavior and a tire type. 
     
     
       4. The electrically assisted power steering system according to  claim 1 , wherein the detection unit is configured to determine the at least one parameter relating to the steering characteristic of the predetermined equipment variant present in the motor vehicle in accordance with a barcode identifier. 
     
     
       5. The electrically assisted power steering system according to  claim 1 , wherein the electronics unit includes a vehicle interface, the vehicle interface being configured to connect with the detection unit, the detection unit external to the motor vehicle.